Tip: Use a Pyrex 8-cup measuring cup (aff link). This is one of the best investments you can make in your kitchen. Great for mixing and pouring all sorts of things (batters, ice cream bases, infused liquors, juices, etc.). It will make pouring your drained cucumber juice into a more storage friendly container a super simple task.
The final amount of juice you get will vary depending on the size and age of your cucumbers.